Staged compressors



April 1968 e. ZOEHFELD 3,375,970

' STAGED GOMPRESSORS Filed May 25, 1966 4 Sheets-Sheet 1 INVENTOR. GUNTHER ZOEHFELD his TTORNEYS April 2, 1968 ZOEHFELD STAGED COMPRESSORS 4 Sheets-Sheet 3 I Filed May 25, 1966 INVENTOR. GUNTHER ZOEHFELD his ATTORNEYS April 1968 ZOEHFELD 3,375,970

Filed May 25, 1966 4 Sheets-Sheet 4 Q INVENTO o o o GUNTHER ZOEHF L A TTORNEYS United States Patent 3,375,970 STAGE!) COMPRESSORS Gunther Zoehfeld, West Hurley, N.Y., assignor to Rotron Manufacturing Compan Inc., Woodstock, N.Y., a corporation of New York Filed May 25, 1966, Ser. No. 552,867 13 Claims. (Cl. 230117) ABSTRACT OF THE DISCLOSURE A regenerative compressor including a motor and a housing, the housing having a pair of annular compressor chambers and a generally annular central cavity surrounding the motor and disposed between the chambers. Each chamber has associated therewith an impeller disposed for coaxial rotation by the motor to generate fluid flow in each chamber between an inlet passage and an outlet passage communicating with that chamber and thecentral cavity. The housing includes an intake port and an exhaust port, each of which communicates with the central cavity for receiving and exhausting the fluid to be compressed. Baflles disposed in the central cavity isolate the respective pairs of inlet and outlet passages to each of the compressor chambers and segment the central cavity into a plurality of secondary chambers so that, by selectively placing the baflles, the compressor can be operated to establish independent, parallel or series fluid flow be tween the intake and exhaust ports.

The present invention relates to compressors containing two or more independent compressor stages which are adapted to be connected for parallel, series, or independent operation. In particular, the invention deals with improved regenerative compressors of this type which are readily manufactured from a few basic components requiring only the simplest modification to yield either parallel, series or independent staging of individual compressor stages contained within a unitary integrated unit.

The concept of interconnecting two or more individual fluid compressors or pumps in parallel or series to obtain either increased flow volume or fluid pressure is, of course, well known. Generally speaking, however, with most types of regenerative compressors, this involves the coupling together of completely separate units through valves, ducts, etc. One obvious disadvantage of using two separate units is that routing of fluid flow for the different compressor staging arrangements introduces additional equipment at the sacrifice of compactness. Furthermore, the manufacture of two individual units instead of one is often economically impractical.

In an attempt to mitigate somewhat the expense and bulk of staging two or more essentially independent compressor units, prior practice has been to power each of the units from the shaft of a common power plant such as a motor or turbine. However much of an improvement this has been, there has remained a requirement for a basic versatile multi-stage compressor unit which lends itself well to economic production and which, at the same time, meets increasingly important requirements for maximum compactness.

It is therefore among the objects of this invention to provide an improved basic compressor unit of the type having separate compressor stages integral therewith and which overcomes the disadvantages of known compressors.

A further object of the invention is to provide a unit of this type in which the separate stages may be interconnected for independent, parallel or series fluid flow through the unit.

A further object of this invention is to provide a compressor containing two separate interconnectable compressor stages arranged to preserve the compactness of the unit.

In brief, these and other objects of the invention are attained in a compressor unit in which a housing is provided with a generally annular central cavity surrounding a compressor motor. A circular compressor chamber is located at either end of the housing and is: associated with an impeller disposed for coaxial rotation with the motor to generate fluid flow between inlet and outlet passages connecting each compressor chamber with the central cavity. Various modes of staging are realized by segmenting the cavity into two or more secondary chambers, each of which communicates with at least one of the inlet and outlet passages leading to the respective compressor chambers. The secondary chambers are disposed, relative to the inlet and outlet passages, to direct fluid flow through the individual compressor stages in the desired manner.

In a preferred form of the invention, the housing is formed with. first and second members each having a generally annular channel divided into inlet and outlet portions communicating with respective inlet and outlet passages. When the housing members are assembled, the channels form a central cavity which surrounds the motor. In this embodiment, the two housing members can be rotatably positioned so that the inlet and outlet portions of the channel in each member are disposed to direct fluid flow to a desired one of the inlet and outlet passages in the other member to achieve various modes of staging.

For a better understanding of the invention, together With additional advantages thereof, reference may be made to the following detailed description, and to the drawings, in which: i

FIGURE 1 is a cross-sectional view of a basic compressor unit constructed in accordance with the invention,

taken along the lines 1-1 in FIGURES 2A and 2B;

FIGURES 2A and 2B are plan views of the sections of the compressor housing taken generally in opposite directions from the lines A A and B-B, respectively, in FIGURE 1, and show the segmenting arrangement of the central cavity for parallel connection of the individual compressor stages;

FIGURES 3A and 3B are plan views of the sections of the compressor housing taken generally in opposite directions from the lines A-A and BB, respectively,

in FIGURE 1, and show a segmenting arrangement of the central cavity for series connection of the individual compressor stages; and r FIGURES 4A and 4B are plan views of the compressor housing sections taken generally in opposite directions from the lines AA and B--B, respectively, in FIG- URE 1, and show a central cavity segmenting arrangement for independent operation of the individual compressor stages.

FIGURE 1 illustrates the basic features of a preferred embodiment of a compressor constructed in accordance with the invention. The compressor includes a housing 10 formed by a pair of similar housing members 10a and 10b and having toroidal or annular compressor chambers 11, 12.. of semi-circular cross section, at either outboard end of the housing. As will be apparent shortly, each compressor chamber 11, 12 comprises the stator of an individual compressor stage. The members 10a and 1011 are suitably fastened together, as by screws 13 inserted through one member 10a and engaging a threaded hole in the other member 10b, Disposed interiorally of the housing between the chambers 11, 12 is a motor 14, which is shown schematically to include a rotor 14a and stator 14]), the rotor being attached to a shaft 16 which is journaled for rotation in the bearings 17 and 18.

At the ends of the shaft 16 are impellers 20, 22 each having a chamber of semi-circular cross section which is complementary to a respective associated compressor chamber 11, 12. Each of the impellers 20, 22 is equipped with a plurality of spaced radial blades 20a, 22a which divide the complementary chamber of the impeller into cavities for imparting motion to the fluid. Protective covers 23, 24 at the ends of the housing 10 and enclosing the impellers 22, 20, respectively, preclude impeller damage or misalignment and seal the housing 10 against air leakage.

Located intermediate the stator chambers 11, 12 and surrounding the motor is a central, generally annular cavity 25 which is formed by the adjacent channels 26 and 27 at the inboard ends of the housing members 10:: and 10b, respectively. An O-ring seal 29 ensures an adequately air-tight fit between the two housing members 10a and 10b. Positioned along portions of the opposing faces 26a and 27a of the channels 26, 27 are muffling elements 28 constructed from a sound absorbent material and held in place by perforated retainers 31 and 32, as seen also in FIGURES 2A and 2B. A more detailed explanation of the mufller arrangement and its function may be found in the copending application Ser. No. 517,412, filed Dec. 29, 1965, and assigned to the assignee of the present invention.

As will be better apparent from the subsequent figures, each of the torodial chambers 11, 12 is ducted to the central cavity 25 by inlet and outlet ducts or passages which are isolated from one another by baffles placed in the central cavity 25 to segment the cavity 25 into two or more secondary chambers. Upon rotation of the impellers 20, 22 pressure builds up in the toroidal chambers 11 and 12 between the respective inlet and outlet passages and fluid flow is generated through the compressor. Each of the torodial compressor chambers 11, 12 and the respective impellers 20, 22 associated therewith comprise an individual compressor stage which, by properly arranging the relative positions of the respective inlet and outlet passages of each of the individual stages and by selectively disposing the baffles segmenting the central cavity 25 into inlet and outlet cavity portions, may be connected for independent, parallel or series operation.

Turning now to FIGURES 2A and 2B, the relative positions of the inlet and outlet passages of each compressor stage and the position of the cavity-segmenting baffles are shown for parallel connection of the individual compressor stages. FIGURE 2A shows the right-hand housing member 10a Which includes an inlet passage 35 and an outlet passage 36, both of which extend from the channel 27 into the annular chamber 12. Also leading into the channel 27 are an intake port 38 and an exhaust port 40, both located in a common quadrant of the annular central cavity 25. Similarly, the left-hand housing member 10b (FIGURE 2B) has an inlet passage 42 and an outlet passage 44 intercommunicating the hollow channel 26 and the torodial chamber 11. As illustrated, the opposing faces 26a, 27a of the channels 26, 27 are contoured in the vicinity of the inlet and outlet passages to prevent excessive flow turbulence, In the drawings, the entire housing 10 is shown constructed of metal, but it is understood that contouring of the chamber and cavity surfaces may also be accomplished by casting the metal housing so that the chambers and channels are overdimensioned, and then coating the chamber and channel surfaces with a hard-setting plastic or epoxy compound to bring them to the proper dimension, while at the same time allowing the formation of smooth contours which would otherwise be difficult to attain through casting.

Located between the inlet and outlet ducts or passages of the two individual compressor stages is a baffle formed by the batfle plate sections 45a and 45b in each housing member and extending across the cavity 25 formed by the two hollow channels 26 and 27. The baflle blocks any iluid flow through the cavity between the passage pairs 35, 36 and 42, 44. A second baffle formed by the mating baflie plate sections 46a and 46b is located in quadrature with the bafiie plates 45a and 45b. The baffle plate sections 46a and 461) also present a barrier to fluid flow through the cavity 25 between the intake and exhaust ports 38 and 40, thus segmenting the respective channels 26, 27 forming the cavity 25 into an inlet portion communicating with the intake port 38 and an outlet portion communicating with the exhaust port 40.

The bafiie plate sections may be either formed integrally with the housing members 10a, 1017, as illustrated in FIGURE 1 by the baffle sections 45a, 4517, or mounted to the housing members by any suitable fasteners, such as a screw (not shown) inserted through the edges of the plate section and engaging tapped holes in the opposing faces of the annular channels. lthough not explicitly shown, the abutting edges of the baffle plate sections are preferably provided with a layer or gasket of resilient or sealing material to ensure a good seal and proper mating upon fastening the housing members 10a, 1012 together.

Fluid flow patterns through the compressor are represented by the solid and broken lines, the solid lines tracing the flow path of the fluid in the cavity 25 and the broken lines indicating the flow paths through the annular compressor chambers 11 and 12. As is apparent from the drawings, the inlet ducts and 42 of the respective compressor stages each receive input flow from the intake port 38, and the outlet ducts 36 and 44 each communicate with the outlet portion of the gravity 25 leading to the exhaust port 40. Fluid enters through the intake port into the portion or secondary chamber of the cavity 25 joining the inlet passages 35 and 42, and thence passes into the toroidal compressor chambers 11 and 12. With impeller rotation in the direction of fluid flow, the fluid is compressed and emitted from the passages 36 and 44 into the portion of the cavity 25 leading to the exhaust port 40. The two individual compressor stages therefore operate in parallel, the pressure between the inlet and outlet passages of each of the stages being equal and the total flow volume through the compressor unit being increased.

FIGURES 3A and 3B show the arrangement of the individual compressor stages for series connection. In this mode of operation, an additional baffle plate 48 made up of sections 48a and 48b is situated opposite the baflle plate 45, and the left-hand housing member 10b is rotated through 180 with respect to the right-hand housing member 10a. The positions of the inlet and outlet ducts in the complementary housing member are designated in these and subsequent figures by phantom lines. As seen in FIG- URE 3B, the baffle plate sections 48a and b separate the inlet and outlet passages 42, 44- in the housing member 10b and create a third secondary chamber within the cavity 25 when the two halves of the compressor are assembled.

Tracing out the fluid flow patterns through the cornpressor, the fluid enters through the intake port 38 and then enters the inlet passage 42 in the housing member 1011. After compression in the left-hand compressor stage, the fluid exits from the outlet passage 44 and then travels through a portion of the cavity 25 to the inlet passage 35 (FIGURE 3A) associated with the right-hand compressor stage, where the fluid is further compressed. From the outlet passage 36 communicating with the secondary chamber formed between the baffles 45 and 46, the fluid passes into the exhaust port 40. Fluid flow is thus routed completely internally of the compressor for both series and parallel staging.

Referring now to FIGURES 4A and 4B, independent operation of each compressor stage is achieved by the addition of a fourth baffle 50 comprised'of the plate sections 50a and 50b, and an additional pair of intake and exhaust ports 52 and 54, respectively. Following the fiuid flow through the right-hand compressor stage, the fluid enters through the intake port 52 and inlet passage 35, is compressed in the toridal chamber 12, and exits from the outlet passage 36into the secondary chamber communicating with the exhaust port 40. None of the fluid entering the intake port 52 reaches theleft-hand compressor stage, since the baffle 46 and sections 48a, b isolate the inlet passage 42 from the remaining inlet and outlet passages. Similarly, the baflie sections 48a, 45b and baffle together isolate the outlet passage 44, the baflle 50 and sections 45a, 48b isolate the inlet passage 35, and the baffle 46 and sections 45a, 48b isolate the outlet passage 36.

In the left-hand compressor section, fluid is received through the intake port 38 and passes through the inlet passage 42 into the annular compressor chamber 11 where it is compressed. Thereafter, the fluid is exhausted from the outlet passage 44 into the secondary chamber between the bafiles 43 and 50 and passes out through the exhaust port 54.

From the foregoing, it is seen that the described compressor unit is one which is extremely versatile and compact and which, therefore, combines optimum flow volume delivery with minimum equipment bulk. Moreover, since each compressor stage is ducted into a central cavity, the various modes of staging may be easily accomplished by segmenting the cavity to route the fluid flow between inlet and outlet passages in any desired manner. Conversion or manufacture of the unit for parallel, series or independent operation of the individual compressor stages is accomplished through a simple and expeditious modification performed on one or both of the basic housing. members. Thus, with the addition of one baffle and relatively rotating the housing member through 180 degrees, as in FIGURES 3A and 3B, the compressor unit stages may be changed from parallel to series operation. For independently operating stages, one of the housing members is provided with an additional set of intake and exhaust ports, the other basic components of the compressor unit being the same, and each intake and exhaust port is isolated from the others by baffles.

Although the invention has been described with reference to specific embodiments thereof, many modifications and variations, both in form and detail, will occur to those skilled in the art. All such modifications and variations, therefore, are intended to be included within the scope and spirit of the invention as defined in the appended claims.

I claim:

1. In a regenerative compressor, a motor, a housing having a pair of annular compressor chambers and a generally annular central cavity surrounding the motor and disposed between the compressor chambers the cavity having two passage pairs of which each comprises an inlet and an outlet passage ducted to a respective compressor chamber, the housing 'further having an intake port and an exhaust port each communicating with the central cavity for receiving and exhausting, respectively, fluid flow through the compressor; an impeller associated with each of the compressor chambers and disposed for coaxial rotation by the motor to generate fluid flow between the inlet and outlet passages of the respective pairs; and means for isolating the inlet and outlet passages of the respective pairs.

2. A regenerative compressor as defined in claim 1, in which the central cavity is segmented into a plurality of secondary chambers each communicating with at least one of the inlet and outlet passages of the respective pairs.

3. A regenerative compressor according to claim 2, in which: the inlet passages of the respective pairs and the intake port communicate with a first common secondary chamber; and the outlet passages of the respective pairs and the exhaust port communicate with a second common secondary chamber; whereby the compressor is adapted for parallel fluid flow between the respective inlet and outlet passages.

4. In a regenerative compressor, a housing having a annular central cavity disposed between the compressor chambers and provided with two passage pairs, each pair comprising an inlet passage and an outlet passage ducted to a respective compressor chamber, the housing further having an inlet port and an exhaust port each communicating with the central cavity for receiving and exhausting, respectively, fluid flow through the compressor; an impeller associated with each of the compressor chambers and disposed for coaxial rotation to generate fluid flow between the inlet and outlet passages of the respective pairs; means for segmenting the central cavity into a plurality of secondary chambers, one secondary chamber communicating with the inlet passage of one pair and the outlet passage of the other pair, a second secondary chamber communicating with the outlet passage of the one pair and the exhaust port, and a third secondary chamber communicating with the inlet passage of the other pair and the intake port, whereby the compressor is adapted for series fluid flow between the inlet and outlet passages of the separate pairs.

5. In a regenerative compressor, a housing having a pair of annular compressor chambers and a generally annular central cavity disposed between the compressor chambers and provided with two passage pairs, each pair comprising an inlet passage and an outlet passage ducted to a respective compressor chamber, the housing further having an inlet port and an exhaust port each communieating with the central cavity for receiving and exhausting, respectively, fluid flow through the compressor; an impeller associated with each of the compressor chambers and disposed for coaxial rotation to generate fluid flow between the inlet and outlet passages of the respective pairs; means for segmenting the central cavity into a plurality of secondary chambers to isolate the inlet and outlet passages of each pair from the passages of the other pair, with the intake and exhaust ports communicating respectively with the inlet and outlet passages of one pair through separate secondary chambers; and means defining a second pair of intake and exhaust ports communicating, respectively, with the inlet and outlet passages of the other pair through further separate secondary chambers, whereby the compressor is adapted for independent fluid flow between the respective pairs of intake and exhaust ports.

6. A regenerative compressor as defined in claim 1, in which the intake and exhaust ports are located in a common annular quadrant of the central cavity.

7. A regenerative compressor comprising a motor; first and second housing members each having a compressor chamber at an outboard end thereof provided with an inlet and an outlet passage and a generally annular channel at the inboard end thereof divided into inlet and outlet portions communicating with the respective inlet and outlet passages, the channels in the first and second members forming a generally annular central cavity surrounding the motor; and a rotatable impeller associated with each compressor chamber and coaxially mounted to the motor for generating fluid flow between the respective inlet and outlet portions of each channel.

8. A regenerative compressor as defined in claim 7, in which the inlet and outlet portions of each channel intercommunicate, respectively, with the respective inlet and outlet portions of the other channel, whereby the compressor is operable to establish parallel fluid flow between the respective inlet and outlet portions.

9. A regenerative compressor as defined in claim 7, in which the inlet portion of one channel is disposed to receive fluid flow from the outlet portion of the other channel, whereby the compressor is adapted to establish series fluid flow between the inlet portion of the other channel and the outlet portion of the one channel.

10. A regenerative compressor in accordance with claim 7, wherein the inlet and outlet portions of the respective channels are disposed so as to be isolated from each of the other portions, whereby the compressor is adapted to establish fluid flow between the inlet and outlet passages associated with one compressor chamber independently of the fluid flow through the inlet and outlet passages associated with the other compressor chamber.

11. A regenerative compressor as set forth in claim 7, wherein the inlet and outlet portions of the respective chambers are divided by baifie means disposed to segment the central cavity into a plurality of separate secondary chambers.

12. A regenerative compressor as defined in claim 7, wherein the first and second housing members are relatively rotatable.

13. A compressor unit comprising: a motor including a rotor; a housing having an annular compressor stator chamber formed integrally with the housing at either end thereof and a generally annular central cavity disposed between the stator chambers and surrounding the motor, each of the stator chambers including an inlet and outlet passage for ducting the respective chambers to the central cavity, the housing further having an intake port and an exhaust port communicating with the central cavity for receiving and exhausting, respectively, fluid flow through the compressor; and an impeller associated with each of the stator chambers and connected to either end of the rotor 'for coaxial rotation therewith to generate fluid flow between the inlet and outlet passages of the respective stator chambers; and means disposed in the central cavity for isolating the inlet and outlet passages of the respective stator chambers.

References Cited UNITED STATES PATENTS 2,496,496 2/ 1950 Roth et al 103-115 3,022,739 2/1962 Herrick et al 103-109 3,195,468 7/ 1965 Bood 103-109 FOREIGN PATENTS 64,993 10/ 1955 France.

1,373,463 10/ 1964 France.

709,440 8/ 1941 Germany.

7 20,286 4/ 1942 Germany.

870,004 3/1953 Germany.

568,456 4/ 1945 Great Britain.

377,654 6/1964 Switzerland.

HENRY F. RADUAZO, Primary Examiner 

